I agree, go with the sealed duct approach.
My ceiling panel is held in place at the front by the A-pilliar covers. Then I trimmed the ceiling panel to follow the contour of the door openings and used an edge molding to hold it together. Its a clean look and a solid installation. Its also easy to remove the ceiling panel for maintenance.
I used a rubberized edge molding with a metal core and an internal gap that is a little wider to capture the thickness of both the ceiling panel and the body's doorway.
The interior looks fantastic by the way!:thumbsup: